页岩储层纳米孔隙流动模拟研究

页岩气作为一种重要的非常规天然气资源已受到普遍关注，但页岩储层主要发育纳米孔隙，而针对页岩气在
纳米孔喉中运移的研究还相对滞后，这严重制约了页岩气藏的高效开发。针对纳米尺度孔隙，考虑页岩气的吸附解
吸及吸附相表面扩散，自由气的黏性流、滑脱效应及Knudsen 扩散等运移机制，建立了页岩气单相流动数学模型，并开
展了流动模拟研究。模拟结果表明：对于以纳米孔隙为主的页岩基质，甲烷在孔隙壁面的附着及表面扩散、气体滑脱
及Knudsen 扩散等均将影响气体流动，造成表观渗透率显著高于Darcy 渗透率，且孔喉越细小，压力越低，表观渗透率
与Darcy 渗透率相差越大。通过分析各运移机制对页岩气流动的影响，有助于深入了解页岩气运移产出过程，从而指
导页岩气藏的有效、高效开发。

Simulation of Gas Flow in Nano-scale Pores of Shale Gas Deposits

As an important unconventional natural gas resources，shale gas has aroused wide concern. Shale-gas deposits are
abundant in nano-scale pores. However，the study on the gas flow mechanism is still inadequate，which restricts the efficient
development of shale gas reservoirs. For nanometer pores，a novel single component mathematical model of shale gas which
takes into consideration the adsorption-desorption of shale gas，the surface diffusion of the adsorbed phase，Darcy flow，and
slip flow as well as Knudsen diffusion is proposed. The simulation results show that for shale matrix containing a large number
of nano-scale pores，methane adsorbed on the pore，the seepage flow and Knudsen diffusion all exert influences on gas flow and
make the apparent permeability much higher than absolute permeability. The smaller the pore size and the lower the pressure
is，the larger the difference between the apparent permeability and absolute permeability is. The study of the impact of various
transport mechanisms on gas flow is helpful to understand the process of shale gas production and to guide the development of
shale gas reservoir.